Saving body water by optimal reabsorption of water filtered by the kidney leading to excretion of urine with concentrations of solutes largely above that of plasma allowed vertebrate species to leave the aquatic environment to live on solid ground. Filtered water is reabsorbed for 70% and 20% by proximal tubules and thin descending limbs of Henle, respectively. These two nephron segments express the water channel aquaporin-1 located along both apical and basolateral membranes. In the proximal tubule, the paracellular pathway accounts for at least 30% of water reabsorption, and the tight-junction core protein claudin-2 plays a key role in this permeability. The ascending limb of Henle and the distal convoluted tubule are impermeant to water and are responsible for urine dilution. The water balance is adjusted along the collecting system, i.e. connecting tubule and the collecting duct, under the control of arginine-vasopressin (AVP). AVP is synthesized by the hypothalamus and released in response to an increase in extracellular osmolality or stimulation of baroreceptors by decreased blood pressure. In response to AVP, aquaporin-2 water channels stored in subapical intracellular vesicles are translocated to the apical plasma membrane and raise the water permeability of the collecting system. The basolateral step of water reabsorption is mediated by aquaporin-3 and -4, which are constitutively expressed. Drugs targeting water transport include classical diuretics, which primarily inhibit sodium transport; the new class of SGLT2 inhibitors, which promotes osmotic diuresis and the non-peptidic antagonists of the V2 receptor, which are pure aquaretic drugs. Disturbed water balance includes diabetes insipidus and hyponatremias. Diabetes insipidus is characterized by polyuria and polydipsia. It is either related to a deficit in AVP secretion called central diabetes insipidus that can be treated by AVP analogs or to a peripheral defect in AVP response called nephrogenic diabetes insipidus. Diabetes insipidus can be either of genetic origin or acquired. Hyponatremia is a common disorder most often related to free water excess relying on overstimulated or inappropriate AVP secretion. The assessment of blood volume is key for the diagnosis and treatment of hyponatremia, which can be classified as hypo-, eu-, or hypervolemic.
Introduction: Wolfram syndrome, a rare autosomal recessive disorder, is characterised by diabetes insipidus, juvenile diabetes mellitus, optic nerve atrophy and deafness (DIDMOAD).
Case Report: We present a case of a 21-year-old male diagnosed with Wolfram syndrome who underwent cochlear implantation due to progressive hearing loss. The patient first complained of bilateral hearing loss at the age of 8 years.
Summary: Paediatric pituitary adenomas are rare in children and adolescents and differ from adults in both clinical presentation and management. We present the case of a 14-year-old female with primary amenorrhoea secondary to a macroprolactinoma, showing a modest radiological and biochemical response to dopamine agonist (DA) therapy. Despite a 10-month duration of increasing DA therapy, initial symptoms of primary amenorrhoea and hyperprolactinaemia persisted, with new symptoms of weight gain, lethargy and low mood.
Assistant Professor, Department of Obstetrics and Gynaecology, Chettinad Academy of Research and Education, Chettinad Health City, SH 49 A, Kelambakkam 603103, Tamil Nadu, India.
Background: Zoledronic acid (ZA) is widely used for the treatment of osteolytic bone metastases in malignancies and osteoporosis, but it has been associated with renal impairment. In this study, we investigated adverse events (AEs) related to renal and urinary system diseases associated with ZA using the U. S.
